Yes, you can file a tax appeal.
In New Brunswick, as I know it.. There are tax abatements for some buildings/developments that were for 30 years that are in place. If a property sold, then the abatement was adjusted for the sale price by a ratio.. (Price going higher) But that was when the prices were low.. IIf the property is now sold lower than the abatement should adjust. But I am thinking you are not going to go below the original abatement.. as the whole build would have to be reassessed.
What building is this, Spring St? The Heldrich? I am curious as I know most of what is happening here and would like to inquire about it.
What does your agent say? They should know what they are selling!